LARGE-SCALE PRODUCTION OF POLY(3-HYDROXYVALERIC ACID) BY FERMENTATIONOF CHROMOBACTERIUM-VIOLACELEUM, PROCESSING, AND CHARACTERIZATION OF THE HOMOPOLYESTER

A fed-batch process was developed, which allowed biotechnological prod uction of the homopolyester poly(3-hydroxyvaleric acid) [poly(3HV)], i n a mineral salts medium containing valeric acid as carbon source and complex nutrients as supplements by CHromobacterium violaceum at a 10- and 300-L, fermentation scale. This process yielded up to 40 g dry ce ll matter per L fermentation broth, and the cells contained up to 70% (w/w) poly(3HV). Poly(3HV), which was extracted from the cells with ch loroform and was precipitated from this solvent with ethanol, was proc essed to test bars by injection molding or by press processing and to fibers by melt spinning. The unprocessed and processed poly(3HV) mater ial was characterized with respect to the molecular weight and with re spect to thermal, theological, and mechanical properties. It was shown that it is possible to process biodegradable poly(3HV) thermoplastica lly and to obtain a polymer suitable for applications with low strengt h requirements.